1. Field of Invention
This invention relates to a head lamp device for a vehicle, and more particularly, controlling of a lighting region of the head lamp in a horizontal direction.
2. Discussion of Relevant Art
The head lamp of a vehicle is in general operated to form the two different lighting regions of high-beam and low-beam by manual changing-over of them.
Variation of lamp optical axes between the high-beam and low-beam is directed in a vertical direction and the lamp optical axes are not changed in a horizontal rightward or leftward direction. However, when the vehicle runs along a curved corner or turns right or left, if the lamp optical axes are moved in a turning direction to deflect the lighting region, visibility is improved.
In view of the foregoing, there are many proposals in the prior art in which the lamp optical axes are controlled for their movements in the horizontal rightward or leftward direction in response to a steering angle of the steering wheel (for example, a gazette of Japanese Patent Laid-Open No. Sho 62-77249 (1987) or the like). However, the lighting region in such a prior art as above is not changed unless the steering wheel is operated, so that a turning direction can not be lighted at a stage before entering the curved part.
As an example of solving this problem under a combination with a navigation system, there is provided a system described in Japanese Patent Laid-Open No. Hei 2-296550 (1990).
This prior art example improves visibility more by a method wherein a curved part or the like is foreseen in advance in reference to both map information of the navigation system and information of the proper or subject vehicle position on the map, and the lighting region is changed before entering the curved part.
However, in the case that the vehicle runs on a place where no road data is present, there is a possibility that information in a navigation system is not helpful, or the vehicle can not be controlled or a control timing becomes unstable when the vehicle turns out of a planned course at a crossing point or the like.
It may also be feared that a timing of control to change the lighting region is not adequate for a certain vehicle speed.